Growth and characterization of a novel organic NLO crystal: 4 – ethoxy benzaldehyde – n – methyl 4 – stilbazolium tosylate

The organic material 4‐Ethoxybenzaldehyde‐N‐methyl 4‐Stilbazolium Tosylate (EBST) is a new NLO material and new derivative in Stilbazolium Tosylate family. In this work we synthesized the EBST, the derivative of DAST. By slow evaporation method, we have grown the EBST crystal. Powder XRD confirms the crystalline property, the lattice parameters are calculated from single crystal XRD data and the molecular structure also revealed. The crystal system is found as monoclinic. The crystalline perfection is assessed by the high‐resolution X‐ray diffractometry. A single and reasonably sharp peak observed in the diffraction curve indicates that the quality of the crystal is quite good without having any internal structural grain boundaries. The FTIR and proton NMR study confirm the presence of functional groups. From the UV – Vis Far IR absorption spectra the good transparency is revealed. The Kurtz Perry SHG test confirms the NLO property of the EBST crystal grown and it is 11 times greater than urea. The melting point of the grown crystal is found to be 237°C from the DSC curve. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Crystal and molecular structure of the chiral compound 4–(2–methylbutyloxy)phenyl–4–(2-propenyloxy)-benzoate,C21H24O4

The enantiomeric [(S)-(–)-MBP3B] and the racemic form [(±)-MBP3B] of the title compound with the formula C₃H₅O–C₆H₄–CO₂–C₆H₄–OC₅H₁₁ were studied by single crystal analysis at room temperature. (S)-(–)-MBP3B crystallizes in the orthorhombic space group P2₁2₁2₁ with a = 7.835(3) Å, b = 11.093(6) Å, c = 44.820(3) Å and 8 molecules per unit cell. The structure was determined from 966 reflections with intensities > 3σ. The refinement with isotropic temperature factors leads to R = 0.094. The crystals of the racemic form are monoclinic, space group P2₁/a with a = 7.899(5) Å, b = 11.046(6) Å, c = 22.845(12) Å, β = 99.28(3)°, Z = 4.1236 diffractometer data (I > 3σ) were refined by least-squares methods with anisotropic temperature factors for the non-H atoms to R = 0.070. The packing arrangement for both forms shows a layer-like structure with very similar packing coefficients, k = 0.7085 for the pure enantiomer and k = 0.7014 for the racemic form.     

Crystal structure of R(–)–1–Tosyl–2–methylpyrrolidine

The crystal structure of R(–)-1-tosyl-2-methylpyrrolidine has been determined by X-ray structure analysis. The compound crystallizes in the monoclinic space group P2₁ with cell parameters a = 7.858(1), b = 14.929(6), c = 11.128(1) Å, β = 105.42(1)°. The structure has been solved by direct methods and refined to R = 0.046. There are two crystallographically independent molecules A and B in the asymmetric unit. The pyrrolidine ring of molecule A is disordered with atom C4 occupying two possible sites. The S atom has a distorted tetrahedral coordination in both the molecules. Two bifurcated hydrogen bonds are observed. Molecules are held together by hydrogen bonds.     

Phase equilibria in BaB2O4–LiF system and β–BaB2O4 bulk crystals growth

Solid state synthesis, differencial thermal analysis and visual polythermal analysis were applied to study the phase equilibria in BaB₂O₄–LiF system. A phase diagram BaB₂O₄–LiF has been plotted for the first time. The system has proved applicable for growing β–BaB₂O₄ bulk crystals.     

Phase Equilibrium in the System HgSeO4 – H2SeO4 – H2O at 100°C

The solubility of the system HgSeO₄ – H₂SeO₄ – H₂O was studied at 100 °C. The fields of crystallization of HgSeO₄ H₂O and HgSeO₄ were established. The compounds obtamed were identified by means of chemical, X-ray and crystal-optical analysis. The mechanism of the thermal dissociation of the compounds obtained was studied.     

Epitaxial Overgrowth of LiKSO4 on β–K2SO4 Single Crystals

Nucleation of LiKSO₄ (LKS) crystals from non-equimolar solutions may occur epitaxially on the surface of previously nucleated β-K₂SO₄ (KS) crystals. Both compounds evince a profound hexagonal substructure, and have common topological features and similar coordination schemes. Moreover, they may be related by quantitative similarities between their translation parameters and by correspondence between their bond chains along the directions of epitaxy. The planes of epitaxy are (001)_KS, and (0001)_LKS' and on these planes [010]_KS is always parallel to [010]_LKS' with a misfit of 12.19%. Another pair of directions, [11 0]_KS and [100]_LKS' showing a small angular misfit (0.18°), exhibit an even lower linear misfit (3.09%).     

Synthesis and characterization of compounds LixMn1+xFe2–2xO4 with spinel structure in the quasiternary system “LiO0,5 – MnOx – FeOx“

The thermal decomposition of freeze‐dried Li‐Mn(II)‐Fe(III)‐formate precursors was investigated by means of DTA, TG and mass spectroscopy. By the thermal treatment of the prefired precursors between 400 and 1000°C, single phase solid solutions Li_xMn_1+xFe_2–2xO₄ (0 ≤ x ≤ 1) with cubic spinel structure were obtained. To get single phase spinels, special conditions concerning the temperature T and the oxygen partial pressure p(O₂) during the synthesis are required. Because of the high reactivity of the freeze‐dried precursors, in comparison with the conventional solid state reaction, the reaction temperature can be lowered by 200°C. The cation distribution and the properties of the Li‐Mn‐ferrites were studied by chemical analysis, X‐ray powder diffraction and magnetization measurements. It was found that for high substitution rates, almost all lithium occupies the tetrahedral coordinated A‐sites of the spinel lattice AB₂O₄, while at small x‐values, lithium ions are distributed over the tetrahedral and octahedral sites. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)